Desmear etchant and use thereof

Abstract

Disclosed are methods for replenishing adhesion promoting baths from an unstable state without discarding the bath. Methods of adhesion promoting substrates, such as printed wiring boards, using the replenished baths are also disclosed.

What is claimed is:  
     
       1. A method for preparing a composition consisting of one or more permanganate ion sources, one or more hydroxide ion sources and water, wherein the hydroxide ion is present in an amount of from about 25 to about 85 g/L and wherein the composition has a total manganese ion concentration of from about 15 to about 70 g/L, comprising the steps of a) first combining water and an amount of the one or more hydroxide ion sources sufficient to provide a caustic composition of about 1.2 N or lower; b) combining the one or more permanganate ion sources with the caustic composition; and c) then adding the remaining amount of the one or more hydroxide ion sources. 
     
     
       2. The method of  claim 1  wherein the permanganate ion source comprises one or more alkali metal permanganates. 
     
     
       3. The method of  claim 2  wherein the alkali metal permanganate comprises sodium permanganate, potassium permanganate or mixtures thereof. 
     
     
       4. The method of  claim 1  wherein the hydroxide ion source comprises one or more alkali metal hydroxide or alkaline earth hydroxide. 
     
     
       5. The method of  claim 4  wherein the alkali metal hydroxide comprises one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, or cesium hydroxide. 
     
     
       6. The method of  claim 1  wherein the caustic composition is about 1.0 N or lower. 
     
     
       7. The method of  claim 1  wherein the caustic composition is about 0.5 to about 1.2 N. 
     
     
       8. A method for providing substrates having improved peel strength comprising preparing a composition consisting of one or more permanganate ion sources and water, wherein the hydroxide ion is present in an amount from about 25 to about 85 g/L and wherein the composition has a total manganese ion concentration of from about 15 to about 70 g/L, comprising the steps of a) first combing water and an amount of one or more hydroxide ion sources sufficient to provide a caustic composition of about 1.2N or lower; b) combining the one or more permanganate ion sources with the caustic composition; and c) then adding the remaining amount of the one or more hydroxide ion sources; and contacting the substrates with the composition. 
     
     
       9. The method of  claim 8 , wherein the substrate is a printed wiring board. 
     
     
       10. A method for preparing a resinous substrate for subsequent metallization comprising preparing a composition consisting of one or more permanganate ion sources, one or more hydroxide ion sources and water, wherein the hydroxide ion is present in an amount of from about 25 to about 85 g/L and wherein the composition has a total manganese ion concentration of from about 15 to about 70 g/L, comprising the steps of a) first combining water and an amount of the one or more hydroxide ion sources sufficient to provide a caustic composition of about 1.2N or lower; b) combining the one or more permanganate ion sources with the caustic composition; and c) then adding the remaining amount of the one or more hydroxide ion sources; and contacting the substrate with the composition. 
     
     
       11. A method for desmearing resin from the inside wells of holes formed in resinous substrates comprising preparing a composition consisting of one or more permanganate ion sources, one or more hydroxide ion sources and water, wherein the hydroxide ion is present in an amount of from about 25 to about 85 g/L and wherein the composition has a total manganese ion concentration of from about 15 to about 70 g/L, comprising the steps of a) first combining water and an amount of the one or more hydroxide ion sources sufficient to provide a caustic composition of about 1.2N or lower; b) combining the one or more permanganate ion sources with the caustic composition; and c) then adding the remaining amount of the one or more hydroxide ion sources; and contacting the substrates with the composition. 
     
     
       12. A method for etching the surface of a resinous substrates comprising preparing a composition consisting of one or more permanganate ion sources, one or more hydroxide ion sources and water, wherein the hydroxide ion is present in an amount of from about 25 to about 85 g/L and wherein the composition has a total manganese ion concentration of from about 15 to about 70 g/L, comprising the steps of a) first combining water and an amount of the one or more hydroxide ion sources sufficient to provide a caustic composition of about 1.2N or lower; b) combining the one or more permanganate ion sources with the caustic composition; and c) then adding the remaining amount of the one or more hydroxide ion sources; and contacting the substrates with the composition.